The Harrowing Truth?

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Dry Rot

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Can anyone give me some scientific references to the benefits or otherwise of harrowing grassland for worm control?

I have about 25 acres for 10 Highland ponies and it is not practical to poo pick in winter. Also, as everyone is out wintered 24/7, I have to use fields according to the weather and available shelter. The soil is sandy and mostly free draining.

My vet said worm eggs are killed by freezing but another respected source tells me this is not necessarily so. I assume it is a good idea to break up the latrines (small piles of dung) to expose them to the air at least.

Of course, I know the answer is to do lots of FECs, but I just wondered if anyone could save me the trouble by pointing me towards studies that have already been done! I have harrowed some fields but the poo is quite thick in places so I suppose I need to keep moving it. I do worm routinely but, like everyone else, want to keep it to a minimum.
 
I always thought harrowing when poo picking wasn't practical was just to break up the piles of dung that otherwise sour great patches of grass? Can act as a low grade fertiliser too but certainly not for worm control.
 
I always try to harrow on a blisteringly hot day as had it drummed in to me that this was an effective way to kill worm larvae. I am on sandy soil too and finds that what it needs is a good dose of manure so harrowing is ideal. Sorry no scientific evidence, I should imagine the hot sun kills the larvae.
 
Worm larvae cannot survive in dessicated dung, therefore, harrowing done when the ground is dry and likely to stay dry for a few days, can only be beneficial imo.
 
This is my problem. Poo picking in summer is easy enough, I have a machine. The eggs hatch in warm weather and the larvae dessicate in the sun and so that kills them. I also understand that they exhaust themselves in long grass as they migrate up and down the stems according to the humidity and temperature. (On a humid warm day last summer I actually saw this).

But are worm eggs killed by frost? I know some are. I had an infestation of hookworm in my dogs (about 20 dogs at the time). The vet looked the worms up in one of his reference books for me and advised that the eggs were destroyed by salt or frost. I waited for a spell of frost and dosed all the dogs. I have not seen a hook worm since.

It would be great if the frost really does kill worm eggs. I can understand that eggs might survive in those heaps of dung some horses (especially stallions) make as bacterial action might keep them from freezing. But will breaking them up help worm control? Or am I just spreading worm eggs all over my fields?
 
Very interested in the answer to this also. Have you been using this routine for a while? If so are you inadvertantly doing your own science experiment.

I harrow in winter (in frost) and poo pick in the summer and have done this for 3 years now without seeing any increase in worm counts - hence I assume that I'm not just spreading worms all over my fields (otherwise counts would show the impact of this)
 
Good grassland management, of which harrowing is a part will control the worm burden on land and in the horses.
Mixed grazing with sheep or cattle, preferably both disrupts the cycle.
Harrowing on its own is not as effective as the rest of the package.
We have very low worm counts, but have extensive mixed grazing, no poo picking as it is impractical.
 
Unfortunately, I have a complaint called chronic laziness complicated by severe bouts of procrastination!

What I ought to do is collect fresh poo and put it in a warm place to see what hatches, then put another sample in the deep freeze for a week, then repeat the exercise with a thawed sample and see if here is any difference....

I have read that red worm eggs were stored for a year at +5 degrees C, then fed to foals. The foals died.:eek: But up here, we'd expect to get -10C or below at least.

I was just hoping some eager young vet students had already done the work for me....:o:o:o My plan is probably flawed anyway.:rolleyes:
 
I used to think the hard frost killed eggs too, but recently read that they don't :(

Always used to do wormer doses after a few days of hard frost to try to maximise effect.

I usually poo pick during summer, and YO harrows in winter and spring when fields are dry enough to get machinery in. Up til this year, we had very low worm counts, but this year we had worm eggs seen in all three horses, one with tapeworm eggs too. The weather has been very different this year though... previous years we had hard frosts that lasted for weeks, plus snow cover, and dryish summers where the ground at least managed to dry out. This year we had a mild wet winter 2011/12, a mild wet summer, and now we're having a mild wet winter again. I would imagine this is perfect worm weather :rolleyes:
 
I read somewhere that redworm can survive several degress of hard frost.

We have 14 horses and poo picking in winter when the ground is wet, is jut not on. We do pick in summer and keep small paddocks very clean.

We do harrow paddocks which will be rested for several months and also try and take hay off every field in turn.

Our foals ALWAYS go onto clean poo picked grass which has not been grazed for at least 6 months.
 
Harrowing will only spread the worms about unless you harrow and then rest the field-i harrow and rest and worm for tapeworm and encysted redworm twice a year and have only ever had negative egg counts. My fields are rested for approx six months at a time (either winter or summer)
 
I've also read that resting the fields is key to good worm management - but does anyone know why?
If it's not very dry or very cold wouldn't the worms just live in the ground? or do they hatch and die because they can't get access to their host aminal?
 
I do worm egg counts at work, I had a sample that had a a reading of 2500 eggs per gram (you could see 100 eggs in the slide)that I wanted to save for an open day. I put it in the fridge but there was an error in the fridge so it froze. I did a worm egg count on this after it was frozen I couldnt see any eggs at all!

Resting in theory shouls break the life cycle of the worm. As should cross grazing, other animals eat worms and they can't survive inside them therefore breaking cycle.

Harrowing is meant to work in association with other methods.
 
The main reason for harrowing grassland, is to remove, or more correctly break away the top thatch of dead grass, and so allow the new and fresh grass shoots to emerge, without hinderance.

I would take some convincing that harrowing had any effect, at all, upon the life expectancy of parasite eggs. If the multiple treading of sheep's feet doesn't affect the propensity of a worm burden, then neither will harrowing.

If heavy and sustained frosts or freezing conditions had any effect upon any given worm burden, then after the winters which we had in the 60's and late 70's, then we would be forever free. ;) We aren't!! The level of worm burden is affected by the stocking density, I suspect.

When it comes to resting pastures, for the worm burden to dissipate, then after six months, the burden will lessen. For ground to be entirely clear, then 12 to 24 months would be needed.

Alec.
 
Worms will hibernate in the gut and I have somewhere in my head that tapeworm involve a mite somewhere in their life cycle?
But then you could say if you were to say equest pramox to rid of encysted then have a very hard winter?
Does anyone know how long eggs can survive, do they hibernate as such?
 
I shot santa-the reason a hard winter doesn't kill all the worms is that some worms overwinter in the host-hence why you're supposed to worm before turning out after housing animals.
harrowing will spread the poo and allow the worm eggs to dessicate if they're not eaten by horses in the meantime.
 
I've found some information in "Equine Reproduction" by McKinnon and Voss, a standard vet text book, which I'll summarise:

"Most authorities emphasise that pastures should be rotated at intervals of approximately 2 months. Between rotations, pastures should be chain harrowed and mowed to aerate the soil, reduce weed growth, and level the pasture to eliminate standing contaminated water".

Hmm...weed growth in winter?

"From studies done over a 6 year period, parasite larvae survived on pastures at a consistent rate under natural factors related to alternations of heat and cold, sunlight and darkness, and periods of wetness and dryness".

I find that a bit vague, but there is a reference: Bello, T.R.: The Control and Treatment on Internal Parasites. American Heoscht Corp,Animal Health Division, 1978. So, a study by wormer manufacturer thirty years ago?

"In hot, wet, summer weather, and particularly in late spring or early fall, pastures can become practically decontaminated within an 8 week period. However,in cool weather or when it becomes quite cold or with the arrival of more stable temperatures, parasite larvae live longer because they are not stimulated to utilize their energy. Under these circumstances, natural decontamination requires approximately 6 months. In frigid weather, infective larvae will survive even longer". Frigid means cold, so we are no wiser whether freezing kills the larvae or eggs.

Judging from the spelling, these are comments from American scientists and the Americans do not seem as concerned as we are about worm control. Presumably because they have more space and mostly a dryer climate than the UK.
 
I_shot_Santa said:
The main reason for harrowing grassland, is to remove, or more correctly break away the top thatch of dead grass, and so allow the new and fresh grass shoots to emerge, without hinderance.

I would take some convincing that harrowing had any effect, at all, upon the life expectancy of parasite eggs. If the multiple treading of sheep's feet doesn't affect the propensity of a worm burden, then neither will harrowing.

If heavy and sustained frosts or freezing conditions had any effect upon any given worm burden, then after the winters which we had in the 60's and late 70's, then we would be forever free. ;) We aren't!! The level of worm burden is affected by the stocking density, I suspect.

When it comes to resting pastures, for the worm burden to dissipate, then after six months, the burden will lessen. For ground to be entirely clear, then 12 to 24 months would be needed.

Alec.
Click to expand...

From my memory, this reply is probably the closest to all the scientific literature I've ever read on the subject along with the last poster.

To harrow on the field heavily burdened with horse poo would only seek to spread the poo around which, from memory, only serves to spread the worm/larvae burden throughout the ENTIRE feild - not desirable. Freezing temperatures aren't effective at killing worms/larvae but there is some thought that harrowing to spread the poo allows it to break open, expose the larvae to the sun thus killing it. However, I think it has to be a pretty high temperature for this to happen - which is unlikely - especially give our summers!

Larvae survive up to 31 weeks at winter temperatures, compared to up to seven weeks at summer temperatures and they can survive outside of the poo, I think, from memory - need to check this.

As horses have 'poo corners', at least they deposit their poo in relatively small areas around a feild thus reducing contamination so they naturally attempt their own form of worm control.

Bit of useless information for you: Animals like horse have a "zone of repugnancy" whereby they eat around the poo and not close to it. (This is also concerned with attempting to minimise fungal spores.) It is when they are forced to eat closer to the poo and therefore, to grass contaminated with larvae that the lifecycle of the worms are continued. They are forced to do this when there is little grass or overstocked.

I suppose that farmers who traditionally use harrowing to improve the condition of the land, are less concerned with spreading the poo around and worm contamination because a) they graze the land with mixed livestock, b) obessive about resting the land during the winter - as my dad was (he's turning in his grave with the amount of horse I have turned out!!) c) are not as concerned with worming perhaps as us horsey people are as they don't use their animals for performance.

In my opinion, there is no substitute for poo picking and a regular worming programme as resting and harrowing are not suitable for us.
 
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Traditionally, good husbandry was used to keep all forms of livestock in good order. Since the late 60’s people have found it easier to throw a load of chemicals and poisons at the job, so a lot of knowledge and techniques have been lost.
 
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